Pair of two (2) square or triangle truss lighting stand adapters. 45mm. support bar/truss instead of 40mm. like other brands and models. Fits on larger poles! Inner diameter: 40mm. Outer diameter: 45mm. Overall length: 17" Latches slide from 4.5"-15" (on latch center) and lock into place. Safety cotter pin ensures the bolt will not slide out.